Fuel injection apparatus



Aug. 21, 1956 v E A W NPF... Y H d 8 N m e w m. 9 Q m. 7 t V m. I R vw 6 f 6 3 5. H H c 4 J g l o. m- A 9?: m1 m 3 NM 2 mm S @m S INVENTOR MkfiEE 4 R EV United States. Patent FUEL INJECTION APPARATUS Sidney E. Miller, Sulfield, Conn., assignor to American Bosch Anna Corporation, a corporation of New York Application December 13, 1951, Serial No. 261,529

8 Claims. (Cl. 103-2) This invention relates to fuel injection apparatus and has particular reference to a new and improved fuel injection pump of the type adapted to both pump and d1stribute fuel to the combustion chambers of an internal combustion engine or the like.

An object of the invention is to provide a new and improved fuel injection pump of the type employing a face-cam for effecting reciprocation of the pumping plunger.

Another object of the invention is to provide a new and improved cam arrangement for a pump of the type set forth.

Another object is to provide a fuel injection pump embodying my new and improved cam arrangement.

Another object of the invention is to provide a new and improved face-cam construction for pumps of the type set forth wherein the cam is provided with two opposite cam faces each with means for providing a portion of the desired lift.

Another object is to provide a new and improved fuel injection pump of the type employing a face-cam wherein the cam is provided with two opposite cam faces each adapted to provide a portion of the lift.

Another object is to provide a pump of the type set forth wherein the shaft of the face-cam may be employed as the distributing valve or member.

In injection pumps, one of the design limitations encountered has been the stiffness of the face-cam and shaft which have a large force couple applied by the cam roller. This force unbalance must, in the case of a high-pressure pump, be partially neutralized by the use of multiple cam rollers to distribute the reaction forced load.

Furthermore the stroke of the pump must be limited to the lift which it is possible to include in the cam-face profile and a reasonable lift for pumping may easily result in an excessive crabbing angle of the roller on the face-cam.

It is the principal object of the present invention to provide a new and improved face-cam type of injection pump which removes all bending moment from the facecam shaft and allows the face-cam to be made with two opposite cam faces each with a desired proportion of the lift and which reduces the inertia forces of the facecam and shaft since the lift of the cam is only a portion of the lift of the pumping element. While I have found it preferable to make such lift one-half of the lift of the pumping element, it is pointed out that the proportions of the two cam surfaces need not necessarily be such, but that such proportions may be varied as desired and as found desirable in the case of particular pumps.

A further object of the present invention is to provide an injection pump of the type set forth in which the use of multiple cam rollers to distribute the reaction force load is eliminated.

Other objects and advantages of the invention will be apparent from the following descriptionv taken in connection with the accompanying drawings.

2,759,422 Patented Aug. 21, 1956 In the drawings Fig. l is a longitudinal sectional view of an injection pump embodying the invention;

Fig. 2 is a fragmentary view on an enlarged scale illustrating the cam and roller arrangement; and

Fig. 3 is a diagrammatic view illustrating the distributing arrangement.

Referring more particularly to the drawings wherein similar reference characters designate coresponding parts throughout, the pump shown by way of illustration of the invention comprises the housing 10 having a bore in which is journaled the drive shaft 11. In alignment with the drive shaft bore is provided a distributing bore in which is positioned rotary distributor 12 and between the end of the housing or bearing cap 13 in which drive shaft 11 is journaled and said distributor bore is the facecam chamber 14.

Distributor 12 is provided with a pair of oppositely disposed longitudinal distributing slots 15 between which is positioned peripheral groove 16 which communicates with the fuel injection pump through duct 17 which is always in communication with said peripheral groove 16 which in turn is always in communication with slots 15 whereby said slots are always filled with fuel and adapted to discharge the same through outlets 17a, a pair of which is provided in aligned longitudinal relation as shown in Fig. l with said pairs of outlets being disposed radially relative to the distributor bore and distributor 12 as shown in Fig. 3 with the number of said double bands of outlets depending upon the number of cylinders or combustion chambers in which fuel should be injected with one of said outlets being provided for each cylinder or combustion chamber.

Distributor 15 is provided in its end remote from drive shaft 11 with a keyed slot 18 adapted to receive a keyed end 19 for driving shaft 20 of the gear type supply pump which comprises gears 21 and 22 and which is adapted to receive fuel through inlet line 23 from the fuel supply tank and discharge the same at supply pressure through outlet 24 and pipe line 24a to fuel inlet 25 for the fuel injection pump.

'The distributor 12 is provided with the splined hub 26 adapted to receive splined end 27 on drive shaft 11 for driving the distributor and face-cam member 28 which is an integral flange on said distributor 12 as shown.

The fuel injection pump comprises a bore 29 in which is mounted plunger 30 having the longitudinal bore 31 communicating with spill port 32 and also with lubrication port 33. Spill or bypass port 32 is controlled by sleeve 34 which is connected through eccentric shaft 35 and lever 36 to the governor whereby sleeve 34 is automatically adjusted to control the spilling or bypassing of fuel through port 32 into spill chamber 37, which is connected by a pipe line (not shown) to the fuel supply tank, whereby the quantity of fuel delivered by the injection pump to the distributor is controlled through control of the quantity of fuel spilled or bypassed.

vPlunger 31B is provided with the extension 38 on which is seated spring seat 39 which is engaged by spring 40 for effecting return of the plunger on its filling stroke.

Spring seat 39 engages tappet 41 which is guided by guide 42 and which is provided with the pin 43 on which is rotatably mounted roller 44.

In bearing cap 13 is positioned pin 45 on which is rotatably mounted roller 46.

Between rollers 44 and 46 is positioned double facecam 47 which is integral with flange 28 on hub 26 and adapted to be rotated upon rotation of distributor 12 by drive shaft 11.

Double face-cam 47 is a double ramp cam, that is, it

sides thereof, which lobes may be identical or which could be of other proportions of the desired lift so that the injection characteristics may be modified by modification of such cam profiles.

It will be seen that with this arrangement, whereby the lift of each cam may be half as high, or other proportions as desired, that is, the lift is split between the two cams and not embodied in a single cam and that, therefore, the inertia force of the face-cam and shaft is reduced and also bending moment from the face-cam shaft is eliminated thus greatly increasing the practicability of face-cam injection pumps by overcoming the drawbacks previously encountered as hereinabove set forth.

Double cam 47 is provided with a pair of oppositely disposed ramp or lobe portions 47a for each of the pumping strokes to made by the plunger 30 which strokes usually equal the number of cylinders and combustion chambers to which fuel is to be injected by the pump.

In the operation of the pump shown by way of illustration and which embodies the double ramp cam, the rotation of drive shaft 11 effects rotation of cam 47 which through rollers 46 and 44 effects reciprocation of tappet 41 and injection pump plunger 30 and said plunger 30 is driven on its pumping stroke through said cam and tappet arrangement and returned on its filling stroke through spring 40. The quantity of fuel pumped is controlled through spill port 32 and control sleeve 34 as previously described. Fuel pumped by plunger 30 is forced through delivery or check valve 48 into duct 17 from which it passes to groove 16 to distributing slots 15 and as distributor 12 is rotated and said slots 15 are aligned with the successive outlet 1711, this fuel is delivered through said outlet 17a to the desired combustion chambers.

From the foregoing, it will be seen that I have provided a relatively simple, compact and economical fuel injection pump employing a face-cam and wherein the difficulties previously encountered in face-cam type injection pumps are overcome and that simple, efiicient and economical means have been provided for obtaining all of the objects and advantages of the invention.

I claim:

1. In a fuel injection pump, a face-cam having a predetermined lift, said cam having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions and cam followers on opposite sides of said cam and in the same plane, one of said followers being stationary and the other of said followers and said cam reciprocating upon rotation of said cam.

2. In a fuel injection pump, a face-cam having a predetermined lift, said cam having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions, a fixed follower engaging one of said ramp portions and a movable follower on the opposite side of said cam and engaging the other of said ramp portions, said moveable follower and said cam reciprocating upon rotation of said cam.

3. In a fuel injection pump, a face-cam having a predetermined lift, said cam having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions, a fixed follower engaging one of said ramp portions and a movable follower on the opposite side of said cam and engaging the other of said ramp portions and a pumping plunger actuated by said movable follower, said moveable follower and said cam reciprocating upon rotation of said cam.

4. In a fuel injection pump, a face-cam having a predetermined lift, said cam having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions, a drive shaft operatively connected to said face-cam, a fixed follower engaging one of said ramp portions and a movable follower on the opposite side of said cam, a plunger operatively connected to said movable follower, said face-cam being adapted to effect reciprocation of said plunger upon rotation of said drive shaft, said moveable follower and said cam reciprocating upon rotation of said cam.

5. In a fuel injection pump, a face-cam having a predetermined lift, said cam having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions, a drive shaft operatively connected to said face-cam, a fixed follower engaging one of said ramp portions and a movable follower on the opposite side of said cam, a plunger operatively connected to said movable follower, said face-cam being adapted to effect reciprocation of said plunger upon rotation of said drive shaft, said moveable follower and said cam reciprocating upon rotation of said cam, a distributor operatively connected to said drive shaft and a plurality of outlets communicating with said distributor successively upon rotation of said distributor.

6. In a fuel injection pump, a face-cam having a pre--.

determined lift, said cam having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions, a drive shaft operatively connected to said facecam, a fixed follower engaging one of said ramp portions and a movable follower on the opposite side of said cam, a plunger operatively connected to said movable follower, said face-cam being adapted to effect reciprocation of said plunger upon rotation of said drive shaft, said moveable follower and said cam reciprocating upon rotation of said cam, a distributor operatively connected to said drive shaft and a plurality of outlets communicating with said distributor successively upon rotation of said distributor, said face-cam being operatively connected to and rotated simultaneously with said distributor.

7. In a device of the character described, a housing, a drive shaft journalled in said housing, a distributor operatively connected to and adapted to be driven by said drive shaft, a fuel injection pump comprising a bore, a plunger mounted for reciprocation in said bore, the axes of said plunger and said distributor being substantially parallel, a fuel passage between said bore and said distributor, outlets communicating with said distributor successively up'on rotation of said distributor and means for effecting reciprocation of said plunger, said means comprising a face-cam member operatively connected to said drive shaft and driven thereby and having a predetermined lift, said face-cam member having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions and cam followers on opposite sides of said cam and in the same plane, one of said followers being stationary and the other of said followers and said carn reciprocating upon rotation of said cam.

8. In a device of the character described, a housing, a drive shaft journalled in said housing, a distributor operatively connected to and adapted to be driven by said drive shaft, a fuel injection pump comprising a bore, a plunger mounted for reciprocation in said bore, the axes of said plunger and said distributor being substantially parallel, a fuel passage between said bore and said distributor, outlets communicating with said distributor successively upon rotation of said distributor and means for effecting reciprocation of said plunger, said means comprising a face-cam member operatively connected to said drive shaft and driven thereby and having a predetermined lift, said face-cam member having oppositely disposed ramp portions, said ramp portions extending in opposite directions and being other than parallel, each of said ramp portions being adapted to provide a portion of the cam lift and supplementing the lift of the other of said ramp portions, a movable follower between said cam and said plunger and a fixed follower on the opposite side of said cam and a tappet between said fixed movable fol- 15 2,699,766

lower and said plunger, said moveable follower and said cam reciprocating upon rotation of said cam.

References Cited in the file of this patent UNITED STATES PATENTS 205,868 Houston July 9, 1878 608,361 Craig Aug. 2, 1898 755,416 Tuckfield Mar. 22, 1904 1,445,003 Collier Feb. 13, 1923 1,971,601 Dilg Aug. 28, 1934 2,211,741 Elwell Aug. 13, 1940 2,445,266 High July 13, 1948 2,531,202 Deschamps Nov. 21, 1950 Fodor et al. Jan. 18, 1955 

